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Changing control plane configuration options for Amazon Web Services

You can update your control plane machines to reflect changes in your infrastructure or environment by editing values in the control plane machine set specification.

When you save an update to the control plane machine set, the Control Plane Machine Set Operator updates the control plane machines according to your configured update strategy. For more information, see "Updating the control plane configuration".

The following example YAML snippets show provider specification and failure domain configurations for an AWS cluster.

Sample AWS provider specification

You can update your control plane machines to reflect changes in your underlying infrastructure by editing values in the control plane machine set provider specification.

The following example YAML illustrates a valid configuration for an Amazon Web Services (AWS) cluster.

When you create a control plane machine set for an existing cluster, the provider specification must match the providerSpec configuration in the control plane machine custom resource (CR) that the installation program creates.

You can omit any field that has a value set in the failure domain section of the CR.

In the following example, the <cluster_id> string is the infrastructure ID. The infrastructure ID matches the cluster ID that the installation program used during cluster provisioning. If you have the OpenShift CLI (oc) installed, you can obtain the infrastructure ID by running the following command:

$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster
Sample AWS providerSpec values
apiVersion: machine.openshift.io/v1
kind: ControlPlaneMachineSet
metadata:
  name: cluster
  namespace: openshift-machine-api
spec:
# ...
  template:
# ...
      spec:
        providerSpec:
          value:
            ami:
              id: ami-<ami_id_string>
            apiVersion: machine.openshift.io/v1beta1
            blockDevices:
            - ebs:
                encrypted: true
                iops: 0
                kmsKey:
                  arn: ""
                volumeSize: 120
                volumeType: gp3
            credentialsSecret:
              name: aws-cloud-credentials
            deviceIndex: 0
            iamInstanceProfile:
              id: <cluster_id>-master-profile
            instanceType: m6i.xlarge
            kind: AWSMachineProviderConfig
            loadBalancers:
            - name: <cluster_id>-int
              type: network
            - name: <cluster_id>-ext
              type: network
            metadata:
              creationTimestamp: null
            metadataServiceOptions: {}
            placement:
              region: <region>
              availabilityZone: ""
              tenancy:
            securityGroups:
              - filters:
                - name: tag:Name
                  values:
                  - <cluster_id>-node
              - filters:
                - name: tag:Name
                  values:
                  - <cluster_id>-lb
              - filters:
                - name: tag:Name
                  values:
                  - <cluster_id>-controlplane
            subnet: {}
            userDataSecret:
              name: master-user-data

where:

<ami_id_string>

Specifies the Fedora CoreOS (FCOS) Amazon Machine Images (AMI) ID for the cluster. The AMI must belong to the same region as the cluster. If you want to use an AWS Marketplace image, you must complete the OKD subscription from the AWS Marketplace to obtain an AMI ID for your region.

spec.template.spec.providerSpec.value.blockDevices.ebs

Specifies the configuration of an encrypted Amazon Elastic Block Store (Amazon EBS) volume.

spec.template.spec.providerSpec.value.credentialsSecret.name

Specifies the secret name for the cluster. Do not change this value.

spec.template.spec.providerSpec.value.iamInstanceProfile

Specifies the AWS Identity and Access Management (IAM) instance profile. Do not change this value.

spec.template.spec.providerSpec.value.instanceType

Specifies the AWS instance type for the control plane.

spec.template.spec.providerSpec.value.kind

Specifies the cloud provider platform type. Do not change this value.

spec.template.spec.providerSpec.value.loadBalancers

Specifies the internal (int) and external (ext) load balancers for the cluster.

You can omit the external (ext) load balancer parameters on private OKD clusters.
spec.template.spec.providerSpec.value.placement

Specifies where to create the control plane instance in AWS. The following keys in this stanza specify additional details:

region

Specifies the AWS region for the cluster.

availabilityZone

This parameter is in the failure domain configuration and has an empty value here.

If the cluster uses a failure domain, configure this parameter in the failure domain. If you specify this value in the provider specification when using a failure domain, the Control Plane Machine Set Operator ignores it and uses the value in the failure domain.

tenancy

Specifies the AWS Dedicated Instance configuration for the control plane. For more information, see AWS documentation about Dedicated Instances. The following values are valid:

  • default: The Dedicated Instance runs on shared hardware.

  • dedicated: The Dedicated Instance runs on single-tenant hardware.

  • host: The Dedicated Instance runs on a Dedicated Host, which is an isolated server with configurations that you can control.

spec.template.spec.providerSpec.value.securityGroups

Specifies the control plane machines security group.

spec.template.spec.providerSpec.value.subnet

This parameter is in the failure domain configuration and has an empty value here.

If the cluster uses a failure domain, configure this parameter in the failure domain. If you specify this value in the provider specification when using a failure domain, the Control Plane Machine Set Operator ignores it and uses the value in the failure domain.

If the failure domain configuration does not specify a value, the control plane machines use the value in the provider specification.
spec.template.spec.providerSpec.value.userDataSecret

Specifies the control plane user data secret. Do not change this value.

Sample AWS failure domain configuration

To prevent downtime for your application due to the failure of a single Amazon Web Services (AWS) region, you can configure failure domains in the control plane machine set. To use failure domains, you configure appropriate values in the failureDomains section of the ControlPlaneMachineSet custom resource (CR).

The control plane machine set concept of a failure domain is analogous to the AWS concept of an Availability Zone (AZ). The ControlPlaneMachineSet CR spreads control plane machines across more than one failure domain when possible.

When configuring AWS failure domains in the control plane machine set, you must specify the availability zone name and the subnet to use.

Sample AWS failure domain values
apiVersion: machine.openshift.io/v1
kind: ControlPlaneMachineSet
metadata:
  name: cluster
  namespace: openshift-machine-api
spec:
# ...
  template:
# ...
    machines_v1beta1_machine_openshift_io:
      failureDomains:
        aws:
        - placement:
            availabilityZone: <aws_zone_a>
          subnet:
            filters:
            - name: tag:Name
              values:
              - <cluster_id>-subnet-private-<aws_zone_a>
            type: Filters
        - placement:
            availabilityZone: <aws_zone_b>
          subnet:
            filters:
            - name: tag:Name
              values:
              - <cluster_id>-subnet-private-<aws_zone_b>
            type: Filters
        platform: AWS
# ...

where:

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.placement.availabilityZone: <aws_zone_a>

Specifies an AWS availability zone for the first failure domain.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.subnet

Specifies a subnet configuration. In this example, the subnet type is Filters, so there is a filters stanza.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.subnet.filters.values: <cluster_id>-subnet-private-<aws_zone_a>

Specifies the subnet name for the first failure domain, using the infrastructure ID and the AWS availability zone.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.subnet.type

Specifies the subnet type. The following values are valid: ARN, Filters and ID. The default value is Filters.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.placement.availabilityZone: <aws_zone_b>

Specifies an AWS availability zone for an additional failure domain.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.aws.subnet.filters.values: <cluster_id>-subnet-private-<aws_zone_b>

Specifies the subnet name for the additional failure domain, using the infrastructure ID and the AWS availability zone.

spec.template.machines_v1beta1_machine_openshift_io.failureDomains.platform

Specifies the cloud provider platform name. Do not change this value.

Additional resources